1. Field Of The Invention
This invention relates to a reciprocating variable resistance isotonic exercise device for exercising the primary muscles comprising the upper extremities and upper torso, without putting undue stress on the shoulder joint, including an adjustment for accommodating the optimum range of motion associated with persons of varying arm length and including an isotonic resistance mechanism with adjustment for accommodating the optimum exercise resistance associated with persons of varying muscle strength and endurance.
It is well-known in the study of exercise physiology and in the fitness industry that aerobic exercise is optimized when the principal muscles in the upper extremities and upper torso are recruited in exercises that are predominately lower extremities and lower torso intensive.
The principal upper extremity and upper torso muscles include the pectoralis major, pectoralis minor, deltoids, biceps, coracobrachialis, triceps, anterior serratus, and the posteriorserratus, which are more fully described as follows:
1. The pectoralis major muscles are broad flat muscles which extend from the breast bone upward and laterally attaching to the collar bone, acromioclavicular joint of the shoulder and to the humerus bone of the upper arm. The pectoralis major adducts, internally rotates and flexes the upper arm.
2. The pectoralis minor muscles are round muscles, laying under their corresponding pectoralis major muscles and extend upward and laterally from the anterior of the third, fourth and fifth ribs to attach to a small anteriorly protruding bony process of each scapula (the coracoid process). The pectoralis minor adducts and internally rotates the upper arm and assist the inspiration phase of respiration.
3. The deltoid muscle comprises three groups, the anterior, the middle and the posterior deltoids, which arise respectively from the collar bone anteriorly, the acromion of the scapulae in the midline and the posterior spine of the scapulae posteriorly and extend inferiorly as a group to attach to the deltoid tuberosity of the upper arm humerus bone. The deltoids flex, extend and abduct the shoulder joint.
4. The biceps muscles are long round muscles in the anterior of each upper arm which extend from two attachments at the scapulae above and below the shoulder joint and pass downward to cross over the elbow joint and attach to a tuberosity of the radius bone of the forearm. The biceps muscle, therefore, has action over two joints, the shoulder joint and the elbow joint. The biceps flex both the shoulder and elbow joints.
5. The coracobrachialis muscles are short round muscles that take their attachments from the coracoid process of the scapulae anteriorly and pass laterally to attach to the medial mid-line of the humerus bone of the upper arm. The coracobrachialis flexes and medially adducts the upper arm and shoulder.
6. The triceps muscles are long round muscles that attach to the scapulae and humerus bones and extend downwardly to attach to the ulna bone of the forearm. The triceps extend the shoulder and elbow joints.
7. The serratus anterior muscles are a thin sheet of muscle arising from the outer surfaces of the upper eight ribs by a series of fleshy digitations and pass under the scapulae to attach to the medial border of the scapulae. The serratus anterior holds the scapulae against the posterior chest wall providing optimum mechanical postural advantage of the upper spine and shoulder joint.
8. The serratus posterior muscles are a thin sheet of muscle arising from lower cervical and upper thoracic spines and extend downward and laterally to attach to the upper ribs two to five posteriorly. The serratus posterior are important muscles of respiration.
It can be seen from the above explanations that the primary movements required by any effective body exerciser are divided into two primary functional movement patterns, the first being flexion and adduction of the upper arm and flexion of the forearm, and the second being extension and abduction of the upper arm and extension of the forearm.
Various resistance-type exercise devices for exercising the upper body while performing predominately lower body aerobic exercise, such as walking and jogging, are known. However, it has been found that when a person undertakes a program of exercising the upper body muscles by systematic use of such devices, that person often soon abandons the program because the resistance provision is either unadjustably accommodating to the individual user's condition of upper body strength, fails to provide a variable resistance that increasingly challenges the user's upper body muscles as the user increases in strength or provides a form of resistance that is incompatible with the coordination requirements of upper and lower body aerobic exercise, thus rendering the device ineffective or obsolete.
Many of these devices incorporate an elastic member as the resistance means. These devices are substantially ineffective for their intended purpose and may be harmful to the joints of the body since the resistance progressively increases as the elastic member is stretched through the exercise range of motion, thus placing a progressively increasing load on the body joints at the extreme ranges of motion where the joint is at its weakest posture. As well these devices do not provide increasing challenge to the user's muscles once the user has become sufficiently strong enough to overcome the elastic resistance force. Some of these devices restrict the exercise in a limited range of motion, thus delivering a generally ineffective exercise for their intended purpose. Still, a further disadvantage of many of these devices relates to their proper fitting and securing about the user's body. Harsh straps and rigid structures tend to bind with the flesh of the user's body and quickly the devices are discarded due to discomfort. Most of these devices require the manufacturing of various sizes to promote proper fitting, thus increasing the manufacturing costs and therefore decreasing their affordability. Still further, few of these devices are simple to manufacture and therefore are not inexpensive, lightweight and unobtrusive enough to be publicly worn and are not comfortably flexible enough to fit adequately snug so as to prevent abrasion of the user's body during their use.
It is well-known that the preferred method for strengthening muscles, improving muscular endurance and enhancing the aerobic effectiveness of exercise is optimally provided by exercise devices that utilize smooth operating variable isotonic resistance. A smooth operating resistance is compatible with the coordinated movements common to aerobic exercises while a variable isotonic resistance promotes muscular strengthening and endurance by providing an increasing challenge to the muscles as their strength and endurance improve. Thus, to enable a reciprocating variable isotonic resistance exercise device to be used effectively by people having different muscular strength and aerobic endurance, and to enable a user to progress through an exercise regime and to remain challenged as his or her muscular strength and aerobic endurance increases, there is a need for a upper extremity and upper torso exercise device which not only meets the above-stated criteria, but also one in which resistance can be delivered smoothly to promote coordination of movement between the upper and lower body while providing a resistance which can be conveniently increased or decreased according to the specific user's physiological limitations.
2. Description Of The Related Art
Numerous devices for exercising the upper extremities and torso are known. For example, U.S. Pat. Nos. 4,986,537; 4,993,705; 4,961,573; 4,335,872; 4,441,707 and 5,234,395 describe devices in the field of the present invention.
There are three basic forms of resistance utilized in exercise apparatus: isotonic (same tone) exercisers, isometric (same length) exercisers and isokinetic (same speed) exercisers. Isotonic exercisers provide an adjustable non-varying resistance whereby the user's effort must match a set resistance force, such as is common in conventional weight lifting exercises. Isometric exercisers utilize an immovable resistance means with the resistance to joint movement being exactly matched by a counterforce applied either by the user's opposing limb or by an immovable object. Isokinetic exercisers provide a resistance mechanism, usually hydraulic or centripetal, wherein the resistance force is proportionately increased by the speed of the movement of the body part as is common in air resistance and hydraulic resistance exercise machines.
U.S. Pat. No. 4,986,537 (D'Orta) provides an isotonic exerciser for the upper extremities, however, both the direction and range of the upper body exercise motion are extremely limited by this device. The ability of the user to use the device in coordinated exercises such as walking is precluded by the unnatural motion of the exercise, and by the required attachment of the device to the user's upper thighs.
U.S. Pat. No. 4,993,705 (Tolle) incorporates elastic bands to provide resistance force. Because it is desirable to provide a constant resistance (isotonic) to the movement, the use of elastic bands is not desirable. Elastic bands increase the resistance force disproportionately as the elastic band is stretched, thus providing an increasing resistance between mid-joint range of motion and full-joint range of motion, thereby increasing the risk of potential injury to the joint. Also, this resistance means is quickly rendered ineffective as the user's muscles increase in muscular strength and endurance.
U.S. Pat. No. 4,961,573 (Wehrell) describes a device with an elastic tension rope which is wound around a number of pulleys to provide a more uniform loading of the upper body muscles and joints. This device is worn about the user's upper torso and thus the direction of the exercise range of motion is straightforward as in a boxer's punch. This exercise movement does not meet the two primary movements required for an effective upper body exerciser. The direction of exercise motion is inadequate for exercising the normal arm swing motion of aerobic exercise such as walking and jogging. Furthermore, this device is extremely complex and bulky, and thus this device would be relatively expensive to manufacture and would not be sufficiently unobvious to be used by the average consumer while exercising in public.
U.S. Pat. No. 4,335,872 (Elkin) describes a device consisting of a rope passing through a padded flexible tube draped behind and around the neck of a user for use in exercising the upper body during walking exercise. Though this is a simple, lightweight exerciser, it provides no variable resistance, with the rope passing through the flexible tube unobstructed and thereby providing solely isometric-type resistance to the exercise. Isometric resistance is contrary to the smooth reciprocating coordinated movement requirements of aerobic exercise such as walking or jogging.
U.S. Pat. No. 4,441,707 (Bosch) describes a device similar to Elkin's, wherein a rope passes through a tube that encircles behind the user's back. Bosch's device has the same limitations as Elkin's device.
U.S. Pat. No. 5,234,395 (Miller and Colonello) describes an adjustable assymetric-resistance upper body exerciser which includes a generally arcuate belt encircling the waist of a user having a rigid posterior central portion, generally conforming to the shape of the user's back to limit rotation of the device on the body. The belt also has generally flexible anterior portions including a buckle to tighten the belt around the user's waist. A flexible inelastic cord passes through an elongated guide attached to the belt that slidably retains a central portion of the length of the cord, leaving the right and left ends of the cord extending in the anterior direction and terminating in adjustable-lengths in a pair of handles.
A friction snubber is attached to the rigid posterior portion of the belt, in contact with the slidable cord and applying an adjustable friction load to the rope. A user wearing the belt encircling the waist may alternately pull said left and right handles with a tension force generally proportional to the friction load applied to the cord by the snubber. The snubber includes a friction shoe having a resilient support applying a friction load to the cord which is in turn applied by an adjustable knob on a screw passing through the rigid posterior portion of the belt. This permits the user to turn the knob to adjust the friction load on the cord.
However, this design requires the device to be offered in various sizes; the lengths of the belt and elongated guide tube are fixed and do not accommodate to the individual user's waist size. Should the user chose a size which is too large, skin abrasion, due to slippage of the device about the user's waist, would likely result. It is imperative, for the proper functioning of the device, that the lateral margins of the belt and the free ends of the cord be positioned directly over the lateral margins of the user's waist, to thereby prevent chaffing of the user's lateral waist by the cord. Too small a sizing of the device would cause skin abrasion of the lateral waist by the rope. Therefore, the device of the '395 patent must be manufactured in various sizes to promote proper fitting and thereby its optimum function. The free ends of the elongated guide extend anteriorly beyond the flanged portion of the elongated guide and move freely upward and downward as the user flexes and extends his or her arms during use of the device. The repeated stress to the elongated tube by this movement predisposes the free ends of the tube to early fatigue and fracture at their communication with the tangential flanges. Still a further disadvantage of the '395 patent design relates to the rigid posterior central portion of the belt which tends to bind the flesh of the user's back, especially in the obese user. To reduce this discomfort, the user must tightly cinch the belt about the user's waist which may lead to pressure complications secondary to obstruction of blood flow through the skin directly under the rigid posterior central portion. Still a further drawback of this device is the design of the friction applying snubber and the elongated guide means. The snubber design necessitates attachment of the rotating hand knob and the screw biases resilient support to the rigid posterior central portion with the resilient support being subject to early fatigue, thereby substantially reducing the functional life of the snubber mechanism. Another drawback of this device relates to its failure to dissipate the heat produced secondary to the friction forces generated on the cord by the snubber and elongated guide. Consequently, the functional cord life is substantially shortened. Yet a further drawback of this device relates to the expense of manufacturing the device, wherein a layer of friction increasing material must be sewed, glued or otherwise fixed to the inward-facing surface of the belt, the elongated guide tube must be fastened to the belt through its tangential flanges, cylindrical bushings must be attached to opposite ends of the elongated guide to prevent abrasion of the cord by the margins of the elongated guide during use and the rigid posterior central portion must be fastened to the flexible anterior portions of the belt. This manufacturing process is labor intensive and subjects the device to multiple potentials for failure of the product to function for its intended purpose.